Chaotic communication using time-delayed optical systems

We discuss experimental demonstrations of chaotic communication in several optical systems. In each, an erbium-doped fiber ring laser (EDFRL) produces chaotic fluctuations of light intensity onto which is modulated a message consisting of a sequence of pseudorandom digital bits. This combination of chaos and message propagates at a wavelength of similar to 1.5 microns through standard single-mode optical fiber from the transmitter to a receiver, where the message is recovered from the chaos. We present evidence of the high-dimensional nature of the chaotic waveforms and demonstrate chaotic communications through 35 km of single-mode optical fiber at up to 250 Mbit/s, a rate that is, at present, limited only by the speed of our detector electronics.